A novel direct torque control drive used in electrical vehicle

Permanent magnet synchronous motor (PMSM) was widely used in electric propulsion system of electrical vehicle (EV). As a new motor control strategy, direct torque control (DTC) had the advantages of faster torque and flux regulation, elimination of current regulators and PWM generators, robustness to rotor parameters variation, but it suffered from large torque ripple and variable switching frequency. A novel direct torque control (DTC) drive for EV was proposed in this paper. Different from conventional DTC, the new control strategy uses voltage vector selection strategy to determine the applying voltage vector instead of switching table and uses space vector modulation (SVM) to generate the applying voltage vector. Experimental results for PMSM used in Honda Civic 06My Hybrid EV show the novel DTC can reduce torque ripple, decrease the total harmonics of stator current and fix switching frequency compared with conventional DTC.